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Thursday, January 27, 2022, 7:30 p.m.: Geology of the San Gabriel Mountains, with Bill Neill: This presentation will discuss, first, fault displacements in the San Gabriel Mountains which have formed complex topography. Along the north side of the range, from Cajon Pass to Tejon Pass, the very active San Andreas Fault is the tectonic plate boundary between North America and the Pacific plate. Its predecessor, the inactive San Gabriel Fault, is marked by narrow, linear canyons of the San Gabriel River’s West and East Forks and Big Tujunga Canyon, which divide the front range of Mt. Lukens, Mt. Wilson, and Glendora Ridge from high country to the north. The dominant rock types of the range are granitic intrusions and metamorphic schist formed during Mesozoic time – the age of dinosaurs – when California resembled the Andes volcanic chain of South America. Other parts of California have rock units from earlier and later periods that will be mentioned in order to cover the full history.

Bill Neill studied geology at UCLA and Stanford University, then was employed for about 20 years as a petroleum engineer. He has worked about 20 years as a professional herbicide applicator controlling invasive wildland weeds in natural areas, including the San Gabriel Mountains. Bill is currently president of the Los Angeles / Santa Monica Mountains Chapter of CNPS.

Zoom instructions: This will be a Zoom meeting. To join the meeting, click the following link:
Passcode: 795450
Or by telephone:  +1 720 707 2699 (Denver — long distance charges may apply)
Meeting ID: 822 4861 0074   Passcode 795450